https://krishi.icar.gov.in/jspui/bitstream/123456789/28711/1/Dr.%20Rajbir%20Singh_Biological%20Control.pdf

Biological control of postharvest diseases of fruits and vegetables by microbial antagonists: A review

Fungal diseases result in significant losses of fruits and vegetables during handling, transportation and storage. At present, post-production fungal spoilage is predominantly controlled by using synthetic fungicides. Under the global climate change scenario and with the need for sustainable agriculture, biological control methods of fungal diseases, using antagonistic microorganisms, are emerging as ecofriendly alternatives to the use of fungicides. The potential of microbial antagonists, isolated from a diversity of natural habitats, for postharvest disease suppression has been investigated. Postharvest biocontrol systems involve tripartite interaction between microbial antagonists, the pathogen and the host, affected by environmental conditions. Several modes for fungistatic activities of microbial antagonists have been suggested, including competition for nutrients and space, mycoparasitism, secretion of antifungal antibiotics and volatile metabolites and induction of host resistance. Postharvest application of microbial antagonists is more successful for efficient disease control in comparison to pre-harvest application. Attempts have also been made to improve the overall efficacy of antagonists by combining them with different physical and chemical substances and methods. Globally, many microbe-based biocontrol products have been developed and registered for commercial use. The present review provides a brief overview on the use of microbial antagonists as postharvest biocontrol agents and summarises information on their isolation, mechanisms of action, application methods, efficacy enhancement, product formulation and commercialisation.

Exploitation of microbial antagonists for the control of postharvest diseases of fruits: a review

Alternative management technologies for postharvest disease control: The journey from simplicity to complexity

Key message
Maximizing crop yield while at the same time minimizing crop failure for sustainable agriculture requires a better understanding of the impacts of plant breeding on crop genetic diversity. This review identifies knowledge gaps and shows the need for more research into genetic diversity changes under plant breeding.

/pdf/understanding-crop-genetic-diversity-under-modern-plant-58cjm226zc.pdf

Understanding crop genetic diversity under modern plant breeding.

Emerging fungal and oomycete pathogens infect staple calorie crops and economically important commodity crops, thereby posing a significant risk to global food security. Our current agricultural systems — with emphasis on intensive monoculture practices — and globalized markets drive the emergence and spread of new pathogens and problematic traits, such as fungicide resistance. Climate change further promotes the emergence of pathogens on new crops and in new places. Here we review the factors affecting the introduction and spread of pathogens and current disease control strategies, illustrating these with the historic example of the Irish potato famine and contemporary examples of soybean rust, wheat blast and blotch, banana wilt and cassava root rot. Our Review looks to the future, summarizing what we see as the main challenges and knowledge gaps, and highlighting the direction that research must take to face the challenge of emerging crop pathogens. Emerging fungal and oomycete pathogens pose a significant risk to global food security. This Review summarizes factors affecting pathogen introduction and spread and current disease control strategies, and highlights the direction that research must take to face the challenge of emerging crop pathogens.

Threats to global food security from emerging fungal and oomycete crop pathogens

/pdf/sooty-blotch-and-flyspeck-of-apple-etiology-biology-and-3v23dypm8e.pdf

Sooty blotch and flyspeck of apple: etiology, biology, and control.

The use of genetically resistant maize hybrids is the preferred means of control of gray leaf spot, caused by Cercospora zeae-maydis. One problem faced by maize breeders attempting to breed for resistance to gray leaf spot is the high degree of genotype-environment interactions observed in disease trials. In North Carolina gray leaf spot trials conducted at four locations in the western part of the state, we found consistent hybrid-location interactions over the 1995 and 1996 growing seasons. Isolates of C. zeae-maydis from those test locations were evaluated on the same hybrids used in the multilocation testing at a location in central North Carolina that does not have a history of gray leaf spot. The hybrid-isolate interactions observed in the isolate trial mirrored the hybrid-location effects seen in the multilocation testing. Most of the interactions arose from changes in the magnitude of differences between hybrids when inoculated with the isolates rather than from any change in hybrid ranking. Analysis of internal transcribed spacer-restriction fragment length polymorphisms (RFLPs) and mitochondrial rDNA RFLPs of those isolates and others revealed that both type I and type II sibling species of C. zeae-maydis, as well as C. sorghi var. maydis, are isolated from typical gray leaf spot lesions. Breeders should use the most aggressive isolates of C. zeae-maydis to maximize discrimination between genotypes in gray leaf spot trials.

Variation in Aggressiveness Among Isolates of Cercospora from Maize as a Potential Cause of Genotype-Environment Interaction in Gray Leaf Spot Trials.

A new gene for Ug99 resistance from wheat landrace PI 374670 was detected on the long arm of chromosome 7A.
 Wheat landrace PI 374670 has seedling and field resistance to stem rust caused by Puccinia graminis f. sp tritici Eriks. & E. Henn (Pgt) race TTKSK. To elucidate the inheritance of resistance, 216 BC1F2 families, 192 double haploid (DH) lines, and 185 recombinant inbred lines (RILs) were developed by crossing PI 374670 and the susceptible line LMPG-6. The parents and progeny were evaluated for seedling resistance to Pgt races TTKSK, MCCFC, and TPMKC. The DH lines were tested in field stem rust nurseries in Kenya and Ethiopia. The DH lines were genotyped with the 90K wheat iSelect SNP genotyping platform. Goodness-of-fit tests indicated that a single dominant gene in PI 374670 conditioned seedling resistance to the three Pgt races. The seedling resistance locus mapped to the long arm of chromosome 7A and this result was verified in the RIL population screened with the flanking SNP markers using KASP assays. In the same region, a major QTL for field resistance was detected in a 7.7 cM interval and explained 34–54 and 29–36 % of the variation in Kenya and Ethiopia, respectively. Results from tests with specific Pgt races and the csIH81 marker showed that the resistance was not due to Sr22. Thus, a new stem rust resistance gene or allele, either closely linked or allelic to Sr15, is responsible for the seedling and field resistance of PI 374670 to Ug99.

/pdf/mapping-resistance-to-the-ug99-race-group-of-the-stem-rust-160kccq9qf.pdf

Mapping resistance to the Ug99 race group of the stem rust pathogen in a spring wheat landrace

https://pubag.nal.usda.gov/download/21080/PDF

Evaluation of Pseudomonas syringae strain ESC-11 for biocontrol of crown rot and anthracnose of banana ☆

Persimmon trees are important for their fruit as well as their colorful fruit and foliage in the fall. Persimmon fruit (Japanese persimmon, Diospyros kaki cv. Fuyu) were collected in November 2008 from a tree in Windsor, NC, located in the Coastal Plain. Fruit were not symptomatic on the tree but developed dark lesions after harvest. Isolations from six fruit yielded seven isolates of Colletotrichum acutatum J. H. Simmonds. After incubation at 25°C under continuous light for 15 days on potato dextrose agar (PDA), all isolates had gray aerial mycelium, but the inverse sides of the plates of six isolates were maroon and one was beige. Masses of salmon-colored conidia were formed first in the center of the colonies, then were observed scattered across the colonies in older cultures. Conidia were hyaline, one-celled, elliptic with one or both ends pointed, and measured 8.1 to 16.3 × 3.1 to 5 μm. Setae and sclerotia were not observed. There were also dark structures measuring 1 to 10 mm that were partially emb...

S. Williamson

Papers

Sooty blotch and flyspeck of apple: etiology, biology, and control.

Variation in Aggressiveness Among Isolates of Cercospora from Maize as a Potential Cause of Genotype-Environment Interaction in Gray Leaf Spot Trials.

Mapping resistance to the Ug99 race group of the stem rust pathogen in a spring wheat landrace

Evaluation of Pseudomonas syringae strain ESC-11 for biocontrol of crown rot and anthracnose of banana ☆

First Report of Anthracnose Caused by Colletotrichum acutatum on Persimmon Fruit in the United States.